1. Technical Field
The present invention relates to a belt type continuously variable transmission device having a moveable sheave member that pinches a belt between the moveable sheave member and a fixed sheave, and an actuator that moves the moveable sheave member in an axial direction.
2. Related Art
In the related art, a structure is known in which a belt type continuously variable transmission device is incorporated in a motive power transmitting mechanism that transmits motive power of a motive power source of a vehicle to a wheel. In the belt type continuously variable transmission device, a belt is bridged between a drive pulley on the side of the motive power source in the motive power transmission direction and a driven pulley on the side of the wheel. Of the drive pulley and the driven pulley, at least one pulley includes a fixed sheave, and a moveable sheave which can be moved in an axial direction with respect to the fixed sheave. As the belt type continuously variable transmission device, an electrically-driven structure is known in which the moveable sheave is moved in the axial direction by an actuator including an electric motor.
JP 2007-8405 A and JP 2006-29504 A disclose a belt type continuously variable transmission device having a structure in which the moveable sheave is moved in the axial direction by a screw-type actuator including an electric motor. The actuator includes a moveable feed screw member supported on the moveable sheave via a tube member and a bearing, and a fixed-side feed screw member which is locked and fixed on a crank case or a transmission casing and screw-engages the moveable feed screw member. In this structure, by the driving of the electric motor, a motor-side gear supported on the crank case or the transmission casing is rotated, and a gear that intermeshes with the motor-side gear and integral with the moveable feed screw member is rotated and thus moved in the axial direction. In addition, US Patent Publication No. 2013/0092468 discloses a clutch CVT (continuously variable transmission) device on the side of the motive power source.
In the structure described in JP 2007-8405 A, with the driving of the electric motor, the motor-side gear is rotated, and the motive power is transmitted to the gear on the other side so that the moveable sheave is moved toward or away from the fixed sheave and a belt roll diameter is changed. However, because the gear which intermeshes with the motor-side gear is exposed to the outside in a state before the belt type continuously variable transmission device is placed in a gearbox case that stores the pulley, an improvement is desired from the viewpoint of improving the endurance of the gear.
Further, in the structure described in JP 2007-8405 A, because a rotational shaft, the pulley, and the actuator cannot be integrally handled in a compact structure in a state before the belt type continuously variable transmission device is placed in the gearbox case, an improvement is also desired from the viewpoint of facilitating the assembly work.
In addition, in the structure described in JP 2007-8405 A and JP 2006-29504 A, the moveable feed screw member is supported via the bearing on the tube member fixed on the moveable sheave, and the screw portion of the moveable feed screw member is provided on an outer circumferential side of the bearing. Because of this, a diameter of the screw portion becomes large. In this case, improvement is desired from the view point of reduction in the size of the feed screw mechanism.
At least one advantage of the present invention is in the provision of a belt type continuously variable transmission device which can improve endurance of a gear in a structure which transmits a rotational force from an electric motor to a member having a feed screw.
At least one advantage of the present invention is in the provision of a belt type continuously variable transmission device which can facilitate the assembly work while not reducing the endurance of the gear.
At least one advantage of the present invention is in the provision of a belt type continuously variable transmission device which can reduce the size of a feed screw mechanism.